Historical and Physicochemical Analysis of the Clinker Bricks in the Smart Memorial Gymnasium of the Tiancizhuang Campus at Soochow University, China

Abstract

Clinker bricks were popular as a facade material in the United States between the 1890s and the 1930s. However, this material was unknown to Chinese builders and was seldom found in Chinese modern architecture from 1840 to 1949. The Smart Memorial Gymnasium built in the years 1934–1937 in the Tiancizhuang Campus of Soochow University (Suzhou, China) is one of the rare examples of a building featuring clinker bricks in modern China. Notably, those clinker bricks were not imported but locally manufactured. Despite the heritage significance of the Smart Memorial Gymnasium as part of a major historical and cultural site protected at the national level in China, the history and characteristics of those historical bricks have remained virtually unexplored. This study first provides a historical analysis of those bricks, giving insights into the general knowledge of this construction material around that time based on British and American historical sources from the 19th and 20th centuries, with a focus on historical treaties and documents. This analysis sheds light on the raw materials mixtures of clinker bricks, their manufacturing processes, and their architectural applications at the time. Moreover, this study presents a physicochemical analysis of the clinker bricks employed at Soochow University, focusing on the correlation between historical studies and physicochemical characteristics, as well as the materials’ characteristics that respond to the natural environment. X-ray diffraction (XRD), Raman spectroscopy, scanning electron microscopy with energy dispersive spectroscopy (SEM-EDS), and total immersion tests were employed to investigate the physicochemical properties of the bricks at various locations of the Smart Memorial Gymnasium facades. Our findings deepen the knowledge and understanding of clinker bricks transferred from the West to China in the early 20th century. Additionally, our results reveal the chemical composition and physical characteristics of different types of clinker bricks used in the Smart Memorial Gymnasium, outlining practical implications and future research directions. Overall, this study lays a foundation for the heritage recognition and conservation of Chinese clinker bricks.